Michael Faraday
physics
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Liquefaction of gases
- Michael Faraday showed the relation between liquids
- and their gases, liquifying chlorine, euchlorine,
- nitrate of ammonia, hydrochloric acid,
- sulfurous acid, hydrogen sulfide, and carbonic acid
- by drawing gases into bent glass tubes,
- or by sealing liquids in bent glass tubes
- including in them iron and platinum catalysts
- or a little water or mercury at one end,
- and vaporizing them by heating,
- and cooling by evaporation or salted ice.
- He made these experiments with considerable risk
- as tubes of gases under pressure spontaneously exploded.
Processes
- You can liquify ammonia gas by compressing it,
- which releases heat,
- or you can heat liquid ammonia to convert it to a gas.
- If you let liquid ammonia evaporate under low pressure,
- it sucks heat from its environment,
- and if you cool that gaseous ammonia it condenses back to a liquid.
- If you release a condensed gas to the environment,
- in expanding, it sucks heat from its environment,
- and if you compress the gas, it releases its heat.
- Therefore, we see a relationship
- between the state of a chemical
- and the energy latent in it.
Liquefaction of water
- It’s raining in Seattle.
- These clouds were raised from the Pacific
- and are blowing over us
- toward a low-pressure zone near Omaha.
- Great cummulus clouds move grandly
- to reveal random patches of blue sky.
- When I say “it’s raining,”
- I mean that we see scattered wet spots.
- Innumerable drops speckling windows, windshields,
- yards, roofs, trees waving in a gentle breeze,
- sidewalks, baseball caps, and bluejeans
- evaporate and blow away.
Processes that we observe around us every day do not teach us everything that we need to know about the nature of elements; however, the behaviors of the chemical H2O cycle through the gas, liquid, and solid phases visible in clouds, rain, rivers, lakes, bays, snow-capped mountains, and the ice cubes in our chilled drinks.
See also in The book of science:
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